It is well known that the requirements for improved cabinet insulation and sealing the door/cabinet interface in refrigeration appliances are becoming more and more stringent. In order to comply with the United States Department of Energy standards to reduce energy consumption in the coming few years, substantial improvements must be made. However, in order to keep the cost of manufacture of refrigerators and freezers as low as possible, it is, of course, desirable to maintain as much of the prior cabinet design as possible as the improvements are made. With this as a given factor, the most likely source for energy saving improvements and revisions involves the elimination of heat leakage around the door gasket into the storage compartment.
There have been numerous attempts to do this by improvement to the gasket construction itself, such as shown in the Swerbinsky U.S. Pat. No. 4,653,819, issued Mar. 31, 1987, and assigned to the assignee of the present invention. The approach in this prior art reference is primarily to direct the face of the magnetic gasket in a direction as it approaches the peripheral edge surface of the encased walls of the cabinet so that the gasket is not distorted during closing of the door. Other arrangements providing improvements in the structure of the gasket itself, as well as the mounting arrangement on the periphery of the door, defines a main focal point of thinking among refrigeration appliance engineers.
In the prior art patent '819, there is an incidental suggestion that air insulating spaces positioned between the peripheral edge surface of the encased walls and the corresponding face of the door play a role in stopping heat leakage. It has been found, however, that these relatively small captive spaces found very limited additional improvement in the abatement of the heat leakage problem. First, the spaces are formed by parts of the gasket itself so that there still remains a direct conducting heat flow path through the gasket structure itself from outside the compartment to the inside. It has been proven that this direct heat conduction path provides significant heat leakage, and is not prevented by the insulating spaces suggested in the patent. Furthermore, the spaces are all defined by movable parts of the sealing gasket and depend on contact that is governed by the seating of the magnetic seal. In other words, the spaces are formed only as a secondary consideration and any variation in the magnetic seal engagement, such as due to wear, can actually cause the spaces to open up and thereby eliminate any advantage whatsoever.
Another main path of heat conduction is by means of the projection of the case flange into the refrigerated compartment where the flange is subjected to compartment air flow.
By this invention, there is provided a refrigerator cabinet which includes a gasket and a separate auxiliary flap extending between the inner panels of the walls and the liner panel of the door to significantly cut down on heat leakage, and thereby substantially increase the sealing efficiency.